Accurately maneuvering and placing an invasive medical device, particularly in the form of a needle, in a small or/and sensitive location in the body of a patient, is an arduous procedure usually involving considerable know-how and skills evolving from years of experience. For example, placing a needle in an epidural space (e.g., for administering medication) needs to be performed accurately and sensitively in order to avoid harm to adjacent tissues, such as the dura mater or even surrounding nerve tissue and blood vessels. Overshooting of the tip of the needle beyond the epidural space may puncture the dura mater, which can cause a leak of the cerebral-spinal fluid (CSF) from around the spinal cord into the epidural space, leading to post-dural puncture headaches syndrome, and possibly also to complications that may lead to paralysis and even death.
The majority of current injection techniques are “blind” techniques, mainly tactile based. For example, the main technique of epidural access is based on the “loss of resistance technique” (LORT). In LORT, a fluid or air filled syringe is attached to a needle. While the needle is advanced through different layers in the insertion site, the physician taps on the syringe. Inside dense ligament layers, the physician feels a strong resistance, but when crossing the ligamentum flavum and entering epidural space, there is a substantial loss of resistance so that the fluid or air from syringe can be easily pushed into the low-pressured epidural space, thus potentially alerting the physician to stop advancing the needle and stationing in the epidural space.
U.S. Pat. No. 8,920,388, to Slocum, et al., describes an apparatus for providing feedback regarding the material in which tip of the apparatus is located as the tip is advanced into matter of varying resistances. The apparatus responds to a change in pressure, force, or other parameter such that when the tip reaches matter of a certain resistance, a change in the parameter is sensed. The apparatus provides a driving force to a penetrating medical device, such as a needle, when the apparatus tip encounters material of high resistance. When the apparatus tip encounters a low resistance material, no further driving force is applied to the apparatus. An inner core may be advanced into the low resistance material for deployment of a gas or a liquid as desired.
Exemplary teachings and practices in the field of the invention, by the same applicant/assignee of the present disclosure, are provided in WIPO PCT Pat. Appl. Int'l. Pub. Nos.: WO 2014/097301; and WO 2011/158227.